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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 15 |
| 3 | 40 |
| 4 | 99 |
| 5 | 212 |
| 6 | 429 |
| 7 | 800 |
| 8 | 1430 |
| 9 | 2424 |
| 10 | 3978 |
| 11 | 6288 |
| 12 | 9690 |
| 13 | 14520 |
| 14 | 21318 |
| 15 | 30624 |
| 16 | 43263 |
| 17 | 60060 |
| 18 | 82225 |
| 19 | 110968 |
| 20 | 148005 |
| 21 | 195052 |
| 22 | 254475 |
| 23 | 328640 |
| 24 | 420732 |
| 25 | 533936 |
| 26 | 672452 |
| 27 | 840480 |
| 28 | 1043460 |
| 29 | 1286832 |
| 30 | 1577532 |
| 31 | 1922496 |
| 32 | 2330445 |
[1,4,15,40,99,212,429,800,1430,2424,3978,6288, 9690,14520,21318,30624,43263,60060,82225,110968, 148005,195052,254475,328640,420732,533936,672452, 840480,1043460,1286832,1577532,1922496,2330445] |